Rafflesia manillana

Scientific name: Rafflesia manillana Teschem. emmend. Madulid & Agoo

Family: Rafflesiaceae

Description: Open flower 11 to 16 cm in diameter, with 5 perigone lobes, dotted with warts. Diaphragm incurved, 7 to 12 cm across, upper surface whitish in bud and in newly opened flower, turning brownish. Windows in lower surface round, rarely coalesced. Ramenta numerous, with short stalk and rounded top. Disk with minute processes. Male and female flowers in separate plants.

Distribution: Philippines: Samar (Basey). Endemic.

Habitat: In lowland primary forest. Usually on forest floor attached to a Testrastigma vine, but may also be attached on the vine above ground.

Conservation status: Critically Endangered. This species is so far known only to occur in the lowland forests in Basey, Samar though it is likely to be found in the forests in neighboring municipalities. The DENR Conservation Staff in Region VIII headed by Technical Director Manolito Ragub reports that they have located populations of the species in about nine sites already in the hinterlands of Basey, Samar. Although the distribution is limited to the habitat of the species inside Samar Island Natural Park and is a protected area, nevertheless, it is threatened by forest destruction such as kaingin and land conversion for agricultural purposes. The rare plant may also be threatened by indiscriminate cutting of the host vine (Tetrastigma sp.) and trampling of the buds by humans and animals. It is listed as Critically Endangered in the DENR List of Threatened Species and needs serious conservation efforts.

Botanical Notes: This species was originally described in 1834 from a collection by Hugh Cuming in Basey, Samar. In 1912 a population of Rafflesia species growing in Mt. Makiling was studied and published by the American botanist, W.H. Brown. He assumed that the Makiling plants were the same species, R. manillana from Samar. In a recent detailed comparative study of the flower morphology of the Rafflesia from Samar and Mt. Makiling Madulid and Agoo (2007) revealed that the flowers from the two provenances are morphologically distinct. This study was further supported by observations of R. manillana in the forests of Basey, Samar made in 2010 and 2011 by the Park and Research Staff of DENR Region VIII, in Tacloban City led by Director Ragub. Hence it is now established that R. manillana is the species found in Basey, Samar and the one in Mt. Makiling is a different species which we named R. panchoana, in honor of the late Professor Juan V. Pancho of UPLB. This is explained in detail in the publications: Madulid, D.A and E. M.G.Agoo, “On the identity of Rafflesia manillana Teschem. (Rafflesiaceae), Philippine Scientist 44:57-70 (2007) and Madulid, D.A., Buot, I. and Agoo, E.M. G “Rafflesia panchoana, a new species from Luzon Island, Philippines, Acta Manillana 55:43-48 (2007).

The endangered “Rafflesia manillana” species featured in the Nov. 5, 2005 issue of Philippine Gardens (Ray Ong, ed.) in The Philippine STAR, is actually R. panchoana Madulid, Buot & Agoo.

Photo: Rafflesia manillana courtesy of Dir. Manolito D. Ragub and his staff, DENR Region VIII, Tacloban City.

For further information write to: Domingo A. Madulid, Philippine National Museum, Botany Division, P. Burgos St., Manila. Tel 5271218. Email: [email protected]